Biology - Parasites and Pathogens Flashcards
What is a disease
Condition that impairs the normal activity of an organism
What is an infectious disease
cause by an agent that is passed from one organism to another
How are infectious diseases spread in humans
touch, faeces, moisture droplets, blood transfusions, insects
What is a non-infectious disease
Not a contagious disease, caused by lifestyle factors such as environmental toxins, nutrition, inheritance (genes)
What are examples of non-infectious diseases
Cancer, diabetes, asthma
What are some examples of infectious diseases
Ebola, Malaria, plague, measles
Define emerging diseases
Infectious disease that has increases in the past 30 years (Ebola)
Define re-emerging diseases
Infectious disease that was once major world-wide, then declined and now has come back
Causes of disease symptoms
Physical or chemical damage to a host organism, insufficient supply of necessary requirements, inappropriate response of organism to an environmental factor
What does a parasite do
- Lives on or in another organism (host)
- Obtains food & shelter from host
- Adapted to particular host species
- host is harmed someway by this relationship
In parasitism, is the host harmed
Yes by the symbiont, causing a disease
Define primary host
It is the definitive host, when it reaches mature form (adult)
Define secondary host
Infected by the larval stages of parasite
Define vector
Organism that transports parasite from one host organism to another
An example of an organism and its primary and secondary host
Primary host for malarial protozoan parasite, Pasmodium, is a mammal.
Secondary host is mosquito
Examples of vectors
Insects that feed on infected animal or plant, which then transfer some parasites to next animal they feed on
Life cycle of parasites - what are these characteristics
Patterns of structural, functional and behavioral adaptations
Whats the attachment and establishment
when parasites require a means of attachment to their host
Define ectoparasites
attach to external surface of host, using hooks and suckers
Define endoparasites
located internally such as in gut or tissues of body
What are the patterns of reproduction in parasites
- produce millions and millions of offspring, to increase chance that some will find new host
- many are hermaphrodites (both eggs and sperm)
Why is timing and coordination important
A fertilised egg must be in right place at right time to be able to enter right host
Example of good timing
production of malaria gametes is also synchronised and mature gametes are released from blood cells into blood plasma at same time of say that host species of mosquito feeds.
What are the two different types of transmission that occurs between hosts
Passive and active transmission
